Temperature‐ and food‐dependent foraging gene expression in foragers of the red imported fire ant Solenopsis invicta Buren (Hymenoptera: Formicidae)

The behavioural plasticity and adaptability of some insects, allowing them to adapt to diverse habitats, is strongly associated with foraging genes (for). The role of the foraging gene is closely related to insect polyphenism and some abiotic and biotic factors. The red imported fire ant Solenopsis invicta Buren (Hymenoptera: Formicidae) has successfully expanded its global range and is considered as a model insect because of its adaptability to a range of environmental factors. We use a quantitative reverse transcriptase-polymerase chain reaction to study levels of S. invicta foraging (Sifor) gene expression in foragers after changes in temperature and food availability. Sifor expression levels are down-regulated in colonies kept at 18 degrees C and up-regulated in colonies kept at 35 degrees C after transferring individuals from a colony kept at 26 degrees C. Moreover, Sifor expression levels decrease when food is deprived and increase when food is restored in comparison with the control. This shows that Sifor is linked to temperature to a great extent and to food transformations to some extent, and suggests that Sifor may explain the ability of fire ant foragers to acclimatize to daily temperature fluctuations. Further research on for gene functions will generate more data with respect to eliciting its role in ecological adaptation to environmental change.